Merge branch 'development': v0.4.2 – Bugfixes
Fixes #20
* Removes bug where not all admin column values were printed in case of conflicting field slugs
Merge branch 'master' of github.com:Webbgaraget/wg-meta-box into dev/0.5
Updates changelog
Fixes #21
* Adds generic method to enable sortable admin columns
Updates documentation
Fixes #23
* Adds required option
Merge branch 'dev/0.5' into development
Merge branch 'development'
Two hotfixes
* Removes notices when no slug present when rendering admin column
* Removes notices when no sortable parameter present
Merge branch 'development'

Conflicts:
	classes/class-wg-meta-box-input.php
	classes/class-wg-meta-box.php
Hotfix
Fixes #29
* Removes notice about missing index
Fixes #28
* Adds default values for parameters
Updates changelog